Conventional inside rearview mirrors, including rearview mirrors incorporating pivotable actuator mechanisms for moving the rearview mirror case and mirror element between a high reflectivity day position and a low reflectivity night position, use glass mirror elements incorporating scatter proofing materials to reduce glass scattering upon breakage. Typically, such inside rearview mirrors are mounted on the interior of the vehicle driver/passenger compartment at or near the upper edge of the front windshield. During accidents, the driver and/or other passengers can be thrown forwardly toward the windshield, striking the rearview mirror, causing its fracture and dispersement of dangerous glass fragments and shards. To overcome such danger, scatter-preventing layers have been incorporated on the rear of the glass mirror elements in such assemblies, such layers being selected from adhesive tape, various adhesive layers, layers of plastisol, reinforcing layers such as woven fabric or fiberglass mats, and even sheet metal plates adhered to the rear surface of the mirror element with rubber or silicone adhesives. See, for example, the reinforced mirror elements in U.S. Pat. Nos. 3,985,429 and 3,391,895.
However, the prior known safety inside rearview mirrors have failed to accommodate a more recent safety hazard in vehicles equipped with supplemental occupant restraint systems, commonly known as air bags. In such vehicles, and especially those including two air bags, one mounted in the steering wheel post for protection of the driver, and another on the instrument panel area adjacent or aligned with the front passenger seat, sudden deceleration of the vehicle causes deployment of such air bags by rapid expansion in the period of a few milliseconds. The passenger side air bag is typically large enough to protect two occupants, one in the conventional passenger seat adjacent the door and another seated in the center of the front seat. When deployed., such larger, passenger side air bags expand rapidly outwardly away from the instrument panel as well as laterally and then toward the windshield and instrument panel to complete their expansion. Since the inside rearview mirror is typically positioned near the top edge of the center of the windshield but several inches inwardly therefrom on a support arm, such deployment also envelopes and contacts substantially the entire length of the rearview mirror assembly. Such contact is uniform across the viewing surface of the mirror and traps the rearview mirror preventing it from tipping one way or the other. In such position, the mirror is impacted straight back against its support arm which extends outwardly from the windshield creating a sustained, column loading. Such loading forces the mirror element violently toward the day/night actuator mechanism within the mirror case causing it to be thrust forwardly out of its normal supports and against the rear side of the glass mirror element. This results in fracturing of the glass mirror with portions of the glass forced outwardly beyond the mirror case edges in the form of sharp-edged glass shards. If a passenger within the vehicle simultaneously strikes the inner facing surface of the air bag thereby forcing it toward tile windshield, the sustained load on the inside rearview mirror assembly causing the above fracturing action of the day/night actuator is accentuated. The protrusion of the glass shards may impair proper operation by causing puncturing and ultimate failure of the air bag at the critical moment when deployment and resistance to impact is most needed to protect the vehicle occupants.
Accordingly, vehicular air bag systems have generated a new problem which day/night actuated inside rearview mirror assemblies incorporating glass or other fracturable mirror elements must resist, i.e., the avoidance of mirror element fracture and protrusion of shards or pieces which otherwise would puncture and impair proper operation of air bags during air bag deployment. The present invention was conceived as a solution for this problem in such inside rearview mirror assemblies.